This invention relates generally to a four-wheel drive torque transfer mechanism applied to vehicles equipped with an automatic transmission and more particularly to a lubricating system for a four-wheel drive torque transfer mechanism. Conventional four-wheel drive torque transfer mechanisms are lubricated by an oil pump especially provided for the four-wheel drive torque transfer mechanism. Also, splash lubrication using a gear wheel, or chain splashing the oil contained in the transfer casing, are also used. The gear wheel or chain is a part of the power transmitting means between the front wheel driving output shaft and the rear wheel driving output shaft.
Provision of a lubrication oil pump for the torque transfer mechanism raises the cost of the device, requires a more complex construction and also reduces the efficiency of the transfer device. The result is increased fuel consumption by the engine.
Splash lubrication by means of a gear wheel or chain is not capable of reliable lubrication and seizure or wearing of the bearings is liable to occur.
What is needed is a simple and reliable lubricating system for a four-wheel drive torque transfer mechanism.